How do I paint a vanity?

You can choose to use an expresso brown paint--acrylic latex paint in an enamel finish. This kind of paint is made for cabinets. I would do a light sanding, then prime--I would have my primer tinted brown or be prepared to cover a white primer with 2-3 coats of paint. You do not need to put poly over this. I painted my bathroom vanity black with an enamel finish paint/no poly and it lasted for 10 years before I finally replaced it. This is the kind of paint Sherwin Williams will recommend.

Reflows, repair, sand, clean with TSP, prime, and paint then seal.

Do you want to paint it or restain so it still has wood grain??

I love the look of chalk paint on furniture.

Make sure its clean. Lightly sand to remove any gloss. Prime with Kilz primer then paint. Seal with at least three coats of a water based polyurethane to protect the paint.

For an espresso brown, I would lightly scuff sand the oak finish with 400 grit sandpaper. And then I would use general finishes gel stain in Java. You can apply it with a brush, let it sit for a few seconds and then wipe off the excess. Let it dry and then keep building on layers until you like the look. OR brush on each layer without wiping off the excess. Then I would seal with minwax wipe on poly.